Urine: beyond cytology for detection of malignancy

Optical nanomaterial-based detection of biomarkers in liquid biopsy

Liquid biopsy, which is a minimally invasive procedure as an alternative to tissue biopsy, has been introduced as a new diagnostic/prognostic measure. By screening disease-related markers from the blood or other biofluids, it promises early diagnosis, timely prognostication, and effective treatment of the diseases. However, there will be a long way until its realization due to its conceptual and practical challenges. The biomarkers detected by liquid biopsy, such as circulating tumor cell (CTC) and circulating tumor DNA (ctDNA), are extraordinarily rare and often obscured by an abundance of normal cellular components, necessitating ultra-sensitive and accurate detection methods for the advancement of liquid biopsy techniques. Optical biosensors based on nanomaterials open an important opportunity in liquid biopsy because of their enhanced sensing performance with simple and practical properties. In this review article, we summarized recent innovations in optical nanomaterials to demonstrate the sensitive detection of protein, peptide, ctDNA, miRNA, exosome, and CTCs. Each study prepares the optical nanomaterials with a tailored design to enhance the sensing performance and to meet the requirements of each biomarker. The unique optical characteristics of metallic nanoparticles (NPs), quantum dots, upconversion NPs, silica NPs, polymeric NPs, and carbon nanomaterials are exploited for sensitive detection mechanisms. These recent advances in liquid biopsy using optical nanomaterials give us an opportunity to overcome challenging issues and provide a resource for understanding the unknown characteristics of the biomarkers as well as the mechanism of the disease.

Detection of urinary bladder cancer cells using redox ratio and double excitation wavelengths autofluorescence

The optical redox ratio as a measure of cellular metabolism is determined by an altered ratio between endogenous fluorophores NADH and flavin adenine dinucleotide (FAD). Although reported for other cancer sites, differences in optical redox ratio between cancerous and normal urothelial cells have not previously been reported. Here, we report a method for the detection of cellular metabolic states using flow cytometry based on autofluorescence, and a statistically significant increase in the redox ratio of bladder cancer cells compared to healthy controls. Urinary bladder cancer and normal healthy urothelial cell lines were cultured and redox overview was assessed using flow cytometry. Further localisation of fluorescence in the same cells was carried out using confocal microscopy. Multiple experiments show correlation between cell type and redox ratio, clearly differentiating between healthy cells and cancer cells. Based on our preliminary results, therefore, we believe that this data contributes to current understanding of bladder tissue fluorescence and can inform the design of endoscopic probes. This approach also has significant potential as a diagnostic tool for discrimination of cancer cells among shed urothelial cells in voided urine, and could lay the groundwork for an automated system for population screening for bladder cancer.

Cytological and morphometric study of urinary epithelial cells with histopathological correlation

This study has been done to asses the utility and accuracy of urinary cytology and morphometric study of exfoliated cells in early detection and follow-up of urothelial neoplasms and thereby help to reduce the disease-related mortality and morbidity. A total 100 patients with urinary symptoms were studied by cytological examination of urine along with morphometric analysis of suspicious epithelial cells. Immunostaining to detect CK-20 expression and p53 over expression was done in smears showing atypical cells. Histopathological confirmation was done in cases which were suspicious on cystoscopy. P value was determined by using unpaired t-test. Statistically significant difference was found between neoplastic and non-neoplastic lesions of the urinary bladder as far as morphometry is concerned. Urinary cytology along with morphometry is an important tool in early detection of urothelial neoplasms. It is also helpful to find out the recurrences during post-operative follow-up period. Overexpression of CK-20 and p53 immunostain in cytology can act as an adjunct to the cytological diagnosis.

Diagnostic significance of atypical category in the voided urine samples: A retrospective study in a tertiary care center

Background:

Voided urine samples continue to play an important role in the surveillance of urothelial malignancy and also as a screening mode for high risk patients. In some cases, it is difficult to reliably distinguish changes induced by inflammation, stone or other reactive condition from neoplasm, and these cases are categorized as atypical. The aim of our study is to evaluate the prevalence and the significance of atypical diagnosis in the voided urine samples and also to identify the cytomorphologic features that are seen more frequently in the atypical malignant urine samples.

Materials and Methods:

All voided urine cytology samples with a diagnosis of atypical urothelial cells, between the period of 2000 and 2009, were obtained from the cytology database. Only those cases with histologic follow-up were included in the study. The cytology and the histology slides were retrieved and reviewed. The following parameters were evaluated: cellularity, cell clusters, nuclear membrane irregularities, hyperchromasia and India-ink type nuclei, the presence of spindle cells and the cytoplasmic characteristics.

Results:

Out of 72 voided urine samples included in the study, 49 cases (68%) had a positive histologic diagnosis of urothelial malignancy in the follow-up histology; of these (55%) were high-grade urothelial carcinoma. Increased cellularity, papillary cell clusters, nuclear membrane irregularity, hyperchromasia and India-ink type nuclei were observed more frequently in the atypical malignant urine samples, while cytoplasmic vacuolization were seen more in the negative reactive urine samples.

Conclusion:

The atypical category diagnosis is associated with a significant proportion of urothelial carcinoma. It should be used by the pathologist to convey concern to the clinician in difficult cases that may require close follow-up.

Fluorescence-assisted cytological testing (FACT): Ex Vivo viral method for enhancing detection of rare cancer cells in body fluids

Cytological analysis of body fluids is currently used for detecting cancer. The objective of this study was to determine if the herpes virus carrying an enhanced green fluorescent protein (EGFP) could detect rare cancer cells in body fluids against millions of normal cells. Human cancer cells suspended with normal murine cells were infected with NV1066 at a multiplicity of infection (MOI) of 0.5 and 1.0 for 18 h. Fluorescent microscopy and flow cytometry were used for EGFP detection of cancer cells. EGFP-expressing cells were confirmed as cancer cells with specific markers by immunohistochemistry staining. Limits of detection of cancer cells in body fluid were measured by serial dilutions. Applicability of technique was confirmed with samples from patients with malignant pleural effusions. NV1066 expressed EGFP in 111 human cancer cell lines detected by fluorescent microscopy at an MOI of 0.5. NV1066 selectively infected cancer cells and spared normal cells as confirmed by immunohistochemistry. Sensitivity of detecting fluorescent green cells was 92% (confidence interval [CI] 83% to 97%) at a ratio of 1 cancer cell to 1 million normal cells. EGFP-positive cells were detected by fluorescent microscopy in patients' malignant pleural effusion samples. Our data show proof of the concept that NV1066-induced EGFP expression allows detection of a single cancer cell against a background of 1 million normal cells. This method was demonstrated to be a reliable screening tool for human cancer cells in a suspension of normal murine cells as well as clinical specimens of malignant pleural effusions.

The Significance of Atypical Urine Cytology in the Face of Normal Investigations—Is Extended Investigation and Follow-Up Required?

Objective:

To examine the natural history of patients identified with atypical urine cytology in the face of normal investigations, and thus provide guidance on the need for extended follow-up and investigation of such patients.

Patients and methods:

All patients identified over a 2-year period to have atypical urine cytology on Cytospin analysis and Papanicolaou staining were audited over a 5-year follow-up period. Clinical records, histopathology and radiology databases were independently searched. Patients were intensively investigated with cystoscopy and a range of upper tract imaging.

Results:

126 patients were identified to have atypical urine cytology, and 77 of these had no urothelial tumour found. In these normal patients, only 12/48 who had further samples taken showed persistent atypia. 11/77 normal patients had another urological pathology which may have explained their atypical urine cytology. No patient presenting for the first time later went on to develop urothelial malignancy in the face of negative initial investigations.

Conclusion:

In the group of patients in which cystoscopy and urography show no urothelial malignancy, the finding of atypical urinary cytology does not predict the development of later urothelial tumour, and does not require prolonged follow-up, repeat cytological testing or further imaging.

Malignant atypical cell in urine cytology: a diagnostic dilemma

Aims

The aim of this study was to find out the characteristic morphology of malignant atypical cells which were missed on routine cytology of urine.

Materials and methods

In this retrospective study, we examined detailed cytomorphology of 18 cases of atypical urinary cytology which were missed on routine examination and were further proved on histopathology as transitional cell carcinoma (TCC) of bladder. The cytological features of these cases were compared with 10 cases of benign urine samples.

Results

There were 11 cases of high grade TCC and 7 cases of low grade TCC on histopathology of the atypical urine samples. Necrosis in the background and necrosed papillae were mostly seen in malignant atypical cells. The comet cells and cells with India ink nuclei (single cells with deep black structure-less nuclei) were only observed in malignant atypical cells. The most consistent features in malignant atypical cells were: i) high nuclear and cytoplasmic (N/C) ratio ii) nuclear pleomorphism iii) nuclear margin irregularity iv) hyperchromasia and v) chromatin abnormalities

Conclusion

The present study emphasizes that nuclear features such as high N/C ratio, hyperchromasia and chromatin abnormalities are particularly useful for assessing the malignant atypical cells. Other cytological features such as comet cells and cells with India ink nuclei are also helpful for diagnosis but have limited value because they are less frequently seen.

Association Between Urinary Cytology and Pathology for Nontransitional Cell Malignancies of the Urinary Tract

PURPOSE

Because nontransitional cell carcinoma neoplasms of the urinary tract are rare in Western countries, we examined the association between urinary cytology and pathology evaluations for these tumors.

MATERIALS AND METHODS

An institutional review board approved, retrospective review of a total of 55,946 cytology evaluations in 12,705 patients between 1992 and 2004 was performed for correlation with subsequent histopathology findings. Documented urothelial neoplasms were then correlated with previous cytology results. Nontransitional cell carcinomas were categorized as adenocarcinoma, squamous cell carcinoma and other, including small cell disease, sarcoma, melanoma or lymphoma.

RESULTS

All 108 patients with cytology evaluations showing adenocarcinoma had histological evidence of cancer and 86% had adenocarcinoma in the urinary tract. All 110 patients with squamous cell carcinoma on cytology had cancer, including 47% with primary squamous cell disease. All 42 patients with other nontransitional cell carcinomas on cytology evaluation had cancer, of whom 64% had histological concordance. In a separate analysis of 70 patients who had pathologically confirmed adenocarcinoma 57% had positive prior cytology findings, of whom 19% had histological concordance. Of 85 patients with squamous cell carcinoma 81% had positive prior cytology findings, of whom 60% had histological concordance. Of 83 patients with other nontransitional cell carcinomas 70% had positive prior cytology findings, of whom 31% had histological concordance.

CONCLUSIONS

In our series all patients with nontransitional cell carcinoma cytological results had cancer in the urinary tract. Thus, nontransitional cell carcinoma cytology findings mandate careful urinary tract evaluation. Concordance with histological subclassification on subsequent pathology evaluation ranges from 49% for squamous cell carcinoma to 86% for adenocarcinoma. A majority of patients with nontransitional cell carcinoma malignancies had positive prior cytology findings. However, the concordance with histological subclassification on prior cytology results ranges from 19% for adenocarcinoma to 60% for squamous cell carcinoma.

How long is urinary cytology abnormal after flexible cystoscopy?

OBJECTIVE

To examine the urinary cytological changes caused by flexible cystoscopy and provide clinical guidelines for a reliable time interval for urinary cytological examination after flexible cystoscopy.

PATIENTS AND METHODS

Forty-eight patients attending for flexible cystoscopy were recruited into the study. Each patient was asked to provide eight urine samples before, immediately after and at 1, 2, 7, 14 and 28 days after cystoscopy. Cytospin preparations of the urine samples were made and slides stained using the Papanicolaou stain. Cytology was analysed while unaware of sample origin, by three different cytopathologists.

RESULTS

The cytological changes were characterized by a striking increase in cellularity immediately after flexible cystoscopy, mostly accounted for by urothelial cells. Consistent morphological changes included the formation of 'columnar' cells, papillary clusters, increased nucleo-cytoplasmic ratio and nuclear atypia. These changes were transient, with most disappearing within a day of flexible cystoscopy.

CONCLUSIONS

There are cytological changes, on voided urine cytology, after flexible cystoscopy but they were transient, and urine sent more than a day after flexible cystoscopy should be free from artefactual change caused by instrumentation. These results suggest that clinicians sending urine for cytological analysis should provide information about the nature and timing of any endoscopy so as to avoid false-positive interpretations of urine cytology by the cytopathologist.